Ferrite ceramic composition and coil component

Abstract

A ferrite ceramic composition includes, as main components, from 27.0 mol % to 41.0 mol % of Fe in terms of Fe 2 O 3 , from 16.0 mol % to 24.0 mol % of Ni in terms of NiO, from 23.0 mol % to 37.0 mol % of Zn in terms of ZnO, from 5.0 mol % to 9.0 mol % of Cu in terms of CuO, and from 4.0 mol % to 14.0 mol % of Si in terms of SiO 2 , and as sub-components, relative to 100 parts by mass of the main components, from 0.3 parts by mass to 1.2 parts by mass of Bi in terms of Bi 2 O 3 , from 0.3 parts by mass to 1.2 parts by mass of Co in terms of Co 3 O 4 , from 0.01 parts by mass to 0.25 parts by mass of Mn in terms of Mn 2 O 3 , and from 0.003 parts by mass to 0.030 parts by mass of Cr in terms of Cr 2 O 3 .

What is claimed is: 
     
         1 . A ferrite ceramic composition comprising:
 as main components,   from 27.0 mol % to 41.0 mol % of Fe in terms of Fe 2 O 3 ;   from 16.0 mol % to 24.0 mol % of Ni in terms of NiO;   from 23.0 mol % to 37.0 mol % of Zn in terms of ZnO;   from 5.0 mol % to 9.0 mol % of Cu in terms of CuO; and   from 4.0 mol % to 14.0 mol % of Si in terms of SiO 2 ; and   as sub-components, relative to 100 parts by mass of the main components, from 0.3 parts by mass to 1.2 parts by mass of Bi in terms of Bi 2 O 3 ;   from 0.3 parts by mass to 1.2 parts by mass of Co in terms of Co 3 O 4 ;   from 0.01 parts by mass to 0.25 parts by mass of Mn in terms of Mn 2 O 3 ; and   from 0.003 parts by mass to 0.030 parts by mass of Cr in terms of Cr 2 O 3 .   
     
     
         2 . The ferrite ceramic composition according to  claim 1 , wherein an average crystal grain size of crystal grains in the ferrite ceramic composition is from 0.2 μm to 0.8 μm. 
     
     
         3 . The ferrite ceramic composition according to  claim 1 , wherein an average crystal grain size of crystal grains in the ferrite ceramic composition is from 0.2 μm to 0.5 μm. 
     
     
         4 . The ferrite ceramic composition according to  claim 1 , further comprising:
 a magnetic phase containing at least Fe, Ni, Zn, and Cu and a non-magnetic phase containing at least Si and Zn.   
     
     
         5 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 1 .   
     
     
         6 . The coil component according to  claim 5 , wherein
 the insulator part has a dimension of from 0.95 mm to 1.05 mm or less in a length direction and a dimension of from 0.45 mm to 0.55 mm in a width direction.   
     
     
         7 . The ferrite ceramic composition according to  claim 2 , wherein
 an average crystal grain size of crystal grains in the ferrite ceramic composition is from 0.2 μm to 0.5 μm.   
     
     
         8 . The ferrite ceramic composition according to  claim 2 , further comprising:
 a magnetic phase containing at least Fe, Ni, Zn, and Cu and a non-magnetic phase containing at least Si and Zn.   
     
     
         9 . The ferrite ceramic composition according to  claim 3 , further comprising:
 a magnetic phase containing at least Fe, Ni, Zn, and Cu and a non-magnetic phase containing at least Si and Zn.   
     
     
         10 . The ferrite ceramic composition according to  claim 7 , further comprising:
 a magnetic phase containing at least Fe, Ni, Zn, and Cu and a non-magnetic phase containing at least Si and Zn.   
     
     
         11 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 2 .   
     
     
         12 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil, wherein the insulator part is configured comprised of the ferrite ceramic composition according to  claim 3 .   
     
     
         13 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 4 .   
     
     
         14 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 7 .   
     
     
         15 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 8 .   
     
     
         16 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 9 .   
     
     
         17 . A coil component comprising:
 an insulator part;   a coil that is embedded in the insulator part and includes a plurality of coil conductor layers electrically connected together; and   outer electrodes that are disposed on surfaces of the insulator part and are electrically connected to the coil,   wherein the insulator part is comprised of the ferrite ceramic composition according to  claim 10 .   
     
     
         18 . The coil component according to  claim 11 , wherein
 the insulator part has a dimension of from 0.95 mm to 1.05 mm or less in a length direction and a dimension of from 0.45 mm to 0.55 mm in a width direction.   
     
     
         19 . The coil component according to  claim 12 , wherein
 the insulator part has a dimension of from 0.95 mm to 1.05 mm or less in a length direction and a dimension of from 0.45 mm to 0.55 mm in a width direction.   
     
     
         20 . The coil component according to  claim 13 , wherein
 the insulator part has a dimension of from 0.95 mm to 1.05 mm or less in a length direction and a dimension of from 0.45 mm to 0.55 mm in a width direction.